Listed below are the Major League Baseball teams with the best season win–loss records, as determined by winning percentage (.700 or better).
| Season | Franchise | League | Wins | Losses | Pct. | Games played | Finish | |
|---|---|---|---|---|---|---|---|---|
| 1906 | Chicago Cubs | NL | 116 | 36 | .763 | 152 | Lost 1906 World Series | |
| 1902 | Pittsburgh Pirates | NL | 103 | 36 | .741 | 139 | National League Champions | |
| 1886 | Chicago White Stockings | NL | 90 | 34 | .726 | 124 | Lost 1886 World Series | |
| 1909 | Pittsburgh Pirates | NL | 110 | 42 | .724 | 152 | Won 1909 World Series | |
| 1954 | Cleveland Indians | AL | 111 | 43 | .721 | 154 | Lost 1954 World Series | |
| 2020 | Los Angeles Dodgers | NL | 43 | 17 | .717 | 60 | Won 2020 World Series | |
| 2001 | Seattle Mariners | AL | 116 | 46 | .716 | 162 | Lost 2001 ALCS | |
| 1927 | New York Yankees | AL | 110 | 44 | .714 | 154 | Won 1927 World Series | |
| 1886 | Detroit Wolverines | NL | 87 | 36 | .707 | 123 | 2nd place in National League | |
| 1897 | Boston Beaneaters | NL | 93 | 39 | .705 | 132 | Lost 1897 Temple Cup | |
| 1907 | Chicago Cubs | NL | 107 | 45 | .704 | 152 | Won 1907 World Series | |
| 1931 | Philadelphia Athletics | AL | 107 | 45 | .704 | 152 | Lost 1931 World Series | |
| 1998 | New York Yankees | AL | 114 | 48 | .704 | 162 | Won 1998 World Series | |
| 1887 | St. Louis Browns | AA | 95 | 40 | .704 | 135 | Lost 1887 World Series | |
| 1939 | New York Yankees | AL | 106 | 45 | .702 | 152 | Won 1939 World Series |
With shorter schedules (fewer than 100 games before 1884), it was more common for teams to finish with .700 or better winning percentages, as there was less of the evening-out effect of a longer season, and some seasons had multiple teams, with three in 1884 (between the three leagues that year) and in 1885.
In the list below (minimum 15 games played), six teams finished with better overall winning percentages than the 1906 Cubs, three being in the early years of the National league, and the other three in leagues whose status as "major" is questionable: two in the National Association, whose status as a major league has long been disputed, and the other in the Union Association, which is conventionally listed as a major league, but this has been questioned due to the league's overall lack of playing talent and poor organizational structure.
In addition, contemporary baseball guides did not consider the Union Association to be a major league: the earliest record referencing the Union Association as a major league dates to 1922.[1])
| Season | Franchise | League | Wins | Losses | Pct. | Games played | Finish | |
|---|---|---|---|---|---|---|---|---|
| 1875 | Boston Red Stockings | NA | 71 | 8 | .899 | 79 | National Association Champions | |
| 1884 | St. Louis Maroons | UA | 94 | 19 | .832 | 113 | Union Association Champions | |
| 1872 | Boston Red Stockings | NA | 39 | 8 | .830 | 47 | National Association Champions | |
| 1880 | Chicago White Stockings | NL | 67 | 17 | .798 | 84 | National League Champions | |
| 1876 | Chicago White Stockings | NL | 52 | 14 | .788 | 66 | National League Champions | |
| 1885 | Chicago White Stockings | NL | 87 | 25 | .777 | 112 | Tied 1885 World Series | |
| 1885 | New York Giants | NL | 85 | 27 | .759 | 112 | 2nd National League | |
| 1871 | Philadelphia Athletics | NA | 21 | 7 | .750 | 28 | National Association Champions | |
| 1884 | Providence Grays | NL | 84 | 28 | .750 | 112 | Won 1884 World Series | |
| 1874 | Boston Red Stockings | NA | 52 | 18 | .743 | 70 | National Association Champions | |
| 1873 | Boston Red Stockings | NA | 43 | 16 | .729 | 59 | National Association Champions | |
| 1875 | Philadelphia Athletics | NA | 53 | 20 | .726 | 73 | 2nd National Association | |
| 1885 | St. Louis Browns | AA | 79 | 33 | .705 | 112 | Tied 1885 World Series | |
| 1876 | St. Louis Brown Stockings | NL | 45 | 19 | .703 | 64 | 3rd National League | |
| 1879 | Providence Grays | NL | 59 | 25 | .702 | 84 | National League Champions | |
| 1884 | New York Metropolitans | AA | 75 | 32 | .701 | 107 | Lost 1884 World Series | |
| 1877 | Boston Red Caps | NL | 42 | 18 | .700 | 60 | National League Champions |
The all-time best single season record belongs to the Cincinnati Red Stockings, who posted baseball's only perfect record at 67–0 (57–0 against National Association of Base Ball Players clubs) in 1869, prior to Major League baseball. Their record stretched to 81–0 across the 1870 season before losing 8–7 in eleven innings to the Brooklyn Atlantics in Brooklyn on June 14.[2] [3]